Current interrupting device



April 1953 c. w. RAINEY 2,634,343

CURRENT INTEIRRUPTING DEVICE Filed Aug. 11, 1950 wzm ATTORNEKS i atented Apr. 7, 1953 CURRENT 'INTERRUPTIN G DEVICE Challenor Walters R-ainey, Dearborn, Mich, as-

signor to Ford Motor Company, Dearborn,

Mich, a ooriioration of Delaware Application August 11, 1950, Serial No. 178,940

This inventionis directedto the electrical arts and more specifically to deviceswhich are required to continuously, rapidly, and repetitiously interrupt electric currents either in inductive or non-inductive circuits.

in any device which is required to rapidly and continuously interrupt and re.-establishthe now of an electric current, trouble is encountered at the faces doing the actual breaking of the circuit. ihese troubles are traceable to arcing, pitting, overheating, sticking, oxidation, and transfer or" metal from one contact face to the other. The instant invention has been evolved in an effort to circumvent these diifieulties.

This invention will be particularly described in connection with the distributor of an internal combustion engine but is by no means so limited since it may be used wherever a similar problem of current interruption exists. An example of such is the vibrators conventionally used to produce a pulsating direct current suitable for transformation to give the high Voltage direct current needed to operate radio reception apparatus iron a low voltage storage battery source.

This invention is probably best understood from a study of the drawings in which Figure 1 is a plan View of a distributor current interrupting device embodying the invention.

Figure 2 is an elevation view of the same device.

Figure 3 is an elevation of a metal disc employed in the invention.

Figure i is a sectional view or" this disc with the insulating grommets in place.

Figure 5 is a sectional view of a mechanical modification of the structure shown in Figure 4.

Figure 6 is a plan view of a conventional automotive distributor with the cap removed and incorporating the instant invention.

The vital element in this invention is shown most clearly in Figures 3 and 4 and more particularly in Figure 4. In Figures 3 and 4 the numeral iii identifies a metallic disc. Thi disc is preferably, although not necessarily, made of tungsten or similar refractory conductive metal. This disc IE2 is provided with a central aperture i I (Figure 3) for a purpose which will be obvious as the description proceeds. As shown in Figure 4, disc it is associated with insulating grommet l2. This grommet may be made of any easily fabricated and durable insulating material such as nylon or Bakelite. Figure 4 also shows an insulating washer 13 mounted upon insulating grommet I2 to prevent axial displacement of disc it with respect to insulatin F om-- met 12. While in the drawing, grommet l2 and 4 Claims. (C1. 209 -30) washer 13 have been shown as separate members, it may well be in practice that disc la) can be placed-in a mold and grommet i2 and washer l3 molded about discio in a single piece.

As shown in Figures 1 and 2, the current interrupting apparatus or breaker is generally indicated at i5and comprises a bracket is terminating in'a"contact'supporting ear i2, supporting stationary contact l8 and rocker post it. Retatably mounted on rocker post it but electrically insulated therefrom is rocker arm 26 which supports at its outer end movable contact 25 which is aligned with and abuts stationary contact l8. Rocker arm 29 is urged by spring to rotate clockwise and press movable contact 25 against stationary contact I8. Intermediate the ends of rocker arm 25 is mounted rubbing block 23 which bears against the distributor cam and serves to actuate the rocker arm 2i Disc ill is mounted upon supporting member 2 so that the faces of disc It are parallel to the faces of stationary contact 18 and movable contact 2i and between the faces of these contacts. Supporting element E is in turn supported upon car H. The bore in grommet i2 is sized so that it makes a loose running fit on supporting mentber 24 which serves as a shaft upon which grommet i2 and disc Ill revolve.

Figure 5 demonstates a mechanical variant of the structure shown in Figure 4. In this struc= ture a definite radial clearance is provided between support 2d and grommet 12 in excess of that necessary for a running fit. Similarly axial and radial clearances are provided between the disc Hi and grommet I2 and washer 53. Under certain circumstances, this loose type of fit provides superior rotational qualities as compared to the structures shown in Figure i. it is also helpful to bias the assembly of the disc and grommet l2 eccentrically in the direction shown by the arrow in Figure 5. Any of many possible spring structures may be used for this purpose and the direction of its action should be skewed with regard to the axis of disc it.

In the operation of the distributor, when the circuit through the breaker contact points i3 and 2! is open the space between these contacts significantly exceeds the thickness of disc iii. When the distributor cam (Figure 6) permits the olccla wise movement of rocker arm a solid electrical contact is made from stationary contact iii to disc it, from disc to to movable contact and hence to rocker arm This structure has been found to produce dur ing operation a slow but continuous rotation disc H) and grommet l2 about supporting member 25. The utility of this rotation is at once evident inasmuch as there is so presented a fresh contact surface to each of the contacts continuously. This results in much cooler operation of the contacts and minimizes all of the troubles enumerated above. In addition, wear or deterioration on disc 50 is not serious, hence this disc may be readily and economically replaced.

Applicant is unaware of the exact cause of this rotation. It is thought that in the case of an automotive distributor of the type described at least a part of the turning movement may be derived from the slight looseness inherent in the mounting of rocker upon rocker post l9. However, applicant does not wish to be bound by any theory as to the cause of such rotation.

I claim as my invention:

1. An internal combustion engine distributor comprising a pair of cooperating contacts arranged to repetitiously interrupt the low tension current, a metallic axis mounted parallel to and spaced from the axis of said contacts, and a conducting disc rotatably mounted on said axis and between the faces of said contacts.

2. An internal combustion engine distributor comprising a pair of cooperating contacts arranged to repetitiously interrupt the low tension 4 current, a metallic axis mounted parallel to and spaced from the axis of said contacts and a conducting disc rotatably mounted on said axis and between the faces of said contacts, said conducting disc being insulated from the axis.

3. An internal combustion engine distributor comprising a pair of cooperating contacts arranged to repetitiously interrupt the low tensioncurrent, a metallic axis mounted parallel to and spaced from the axis of said contacts and a conducting disc rotatably mounted on said axis and between the faces of said contacts, said conducting disc being supported on said axis through an insulating grommet.

4. The structure recited in claim 3 in which a substantial radial clearance is provided between the grommet and axis and in which substantial axial and radial clearance is provided between the grommet and the disc.

' CHALLENOR WALTERS RAINEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,223,143 Briggs Apr. 17, 1917 

